The instant invention generally relates to projectile launcher sights which compensate for both the range to the target and the elevation of the shooter relative to the target. More particularly, the instant invention relates to sights for those projectile launchers such as archery bows for which such compensation is necessary.
A projectile launcher launches a projectile at a target at which the shooter aims using a sight. The projectile launched by the projectile launcher follows a ballistic trajectory towards the target, which trajectory is influenced by forces of gravity and drag. The projectile launcher must accordingly be aimed so as to cause the projectile to be launched on a trajectory intersecting the target. The degree to which the initial direction of the projectile differs from the associated straight line path to the target is dependent upon the distance to the target and the degree of influence of gravity or drag upon the projectile, whereby this difference is greater for projectiles launched at relatively lower velocities or which have relatively higher amounts of drag. For example, archery bows, cross bows, sling shots, and low power rifles, such as air rifles, are all subject to significant influences of gravity and drag upon the trajectory of their associated projectiles.
The purpose of the sight on the projectile launcher is to enable the shooter to align the projectile launcher by aiming the sight on the target so as to cause the trajectory of the projectile to intersect the target. For example, when an arrow is shot from an archery bow the departure of the trajectory of the arrow from a straight line can be significant, particularly for distant targets, which requires a means in the associated bow sight to compensate for target range. The departure of the arrow trajectory from a straight line generally depends upon the range to the target and the elevation of the archer relative to that of the target.
More particularly, in the field of archery, an elementary bow sight comprises a single fixed pin, whereby the archer aims the bow by aligning the pin with the target. By maintaining a consistent draw of the bow and a consistent placement of the knock of the drawn arrow relative to the archer""s eye the trajectories of similarly aimed shots can be made consistent. The problem with a single fixed pin however is that the sight will be properly aimed for only one mode of operation of the bow, i.e. for a limited range of target ranges and a limited range of shooting elevations relative to the target elevation.
The prior art teaches a bow sight assembly comprising a plurality of fixed pin sights, each of which is calibrated for a different target range, or combination of target range and shooting elevation relative to the target elevation. However, one disadvantage of such a sight assembly is that each of the fixed pins must be separately calibrated. Furthermore, there is a potential for the archer to use the wrong pin for aiming at the target.
The prior art also teaches a bow sight assembly comprising a mechanism for adjusting the position of either a single pin sight, or a multiple pin sight assembly, or a cross-hair attached at a sight attachment point, in accordance with the range to the target. This type of sight also has the disadvantage of needing to be calibrated for each of the various modes of operation of the bow. Furthermore, the associated mechanism can be expensive and difficult to produce, and difficult to operate properly under conditions of low ambient lighting or when wearing gloves. Examples of this type of sight are disclosed in U.S. Pat. Nos. 2,669,023, 3,487,548, 3,568,323, 3,718,979, 3,787,984, 4,162,579, 4,224,741, 4,368,581, 4,532,717, 4,541,179, 4,643,160, 4,726,123, 5,001,837, 5,092,052, 5,359,780, 5,419,051, 5,465,491 and 5,524,601. While these patents teach various mechanisms for adjusting the height of a sight attachment point, none of these patents teach or suggest the incorporation of a pendulum sight subassembly at the sight attachment point.
The prior art also teaches the use of a combination of front and rear sights, or a telescope having a sighting axis, so as to improve shooting accuracy. However, these sights also require a means for adjustment and calibration to accommodate different ranges and elevations of the archer relative to the target. Examples of this type of sight are disclosed in U.S. Pat. Nos. 2,559,927, 2,667,692, 2,982,026, 3,058,221, 3,063,151, 3,271,863, 4,237,615, 4,417,403, 4,418,479, 4,625,420, 4,961,265, 5,040,300, 5,048,193, 5,092,053 and 5,539,989. While these patents teach various mechanisms for adjusting the orientation of either a combination front and rear sights, or a telescope having a sighting axis, none of these patents teach or suggest the incorporation of a pendulum sight subassembly with such mechanisms.
Another type of archery bow sight taught in the prior art, and in common use, is referred as a pendulum bow sight, which comprises a pendulum having center of gravity and a pivot point located thereabove. The pendulum pivots about one end of a pivot shaft which axis passes through the pivot point, and the other end of the pivot shaft is secured to the archery bow at the sight attachment point. The pendulum is biased so that the center of gravity of the pendulum remains directly below the pendulum pivot pointxe2x80x94the pendulum stays in a vertical positionxe2x80x94regardless of the elevation angle of the archery bow. A sight aiming point is attached to or incorporated on the pendulum. In some commercially available pendulum bow sights, the pendulum is constructed from a rod which incorporates the sight aiming point at the upper end. The pendulum is further provided with a counterweight, a means for adjusting the relative length of the pendulum above the pivot point, and a means for adjusting the position of the counterweight along the lower length portion of the pendulum. In operation, for a target elevation which differs from the elevation of the archer""s eye, the angle of the ray projected from the archer""s eye to the target changes with the range of the target relative to the archer. Therefore, targets of differing ranges cause the archer to incline the bow at correspondingly different angles in order to align the bow sight with the target. The pendulum remains vertical independent of the elevation angle of the archer""s bow, so that the position of the sight aiming point changes relative to the projectile launcher. More particularly for a target below the eye level of the archer, as the target range is increased, the archer must raise the bow in elevation angle to keep the sight aiming point aligned with the target. As the elevation angle of the bow is increased, an associated automatic rotation of the pendulum causes the projected distance between the sight aiming point and the arrow to decrease, which thereby causes the archer to raise the bow in elevation angle more that would have been raised had the sight aiming point been fixed. Therefore, the pendulum sight inherently provides compensation for target range so as to enable the archer to shoot accurately over a range of target ranges. The pendulum bow sight is particularly useful for automatically compensating for target range when shooting from elevated platforms. However, a pendulum bow sight calibrated for shooting from an elevated platform, such as a tree stand, will not be calibrated for shooting from ground level. More particularly, the pendulum bow sight must be calibrated for the conditions of relative elevation between target and shooter under which the sight will be used.
Examples of pendulum bow sights are disclosed in U.S. Pat. Nos. 2,925,656, 3,013,336, 3,521,362, 4,120,096, 4,580,349, 4,616,422, 4,711,036, 4,720,919, 4,794,702, 4,894,921, 4,974,328, 5,121,547, 5,253,423, 5,305,530, 5,347,722 and 5,561,910. While these patents teach various pendulum bow sight assemblies, and disclose a means for adjusting the height of the pendulum sight assembly for calibration thereof, whereby otherwise the height of the pendulum sight assembly remains fixed during operation of the pendulum sight, none of these patents teach or suggest the incorporation of a mechanism for quickly adjusting the height of the pendulum sight assembly during operational conditions, in accordance with a predetermined calibration, so as to accommodate variations in the elevation of the shooter relative to the target.
The instant invention overcomes the above-noted problems by providing an improved sight comprising the combination of a pendulum sight subassembly together with a mechanism for adjusting the position of the pendulum sight subassembly relative to the projectile launcher. The pendulum sight subassembly provides for automatic range compensation, and the position adjusting mechanism provides a means for compensating for the elevation of the shooter relative to the target. This enables the pendulum sight assembly to be calibrated under relatively level shooting conditions, and then used with accuracy under conditions where the elevation of the shooter differs from that of the target. The position adjusting mechanism is provided with an indexing mechanism for setting the position to one of a plurality of precalibrated positions so that the elevation adjustment can be readily made under low light conditions or while wearing gloves.
Accordingly, one object of the instant invention is to provide an improved sight for a projectile launcher which is accurate over a wide range of operating conditions using a single calibration.
A further object of the instant invention is to provide an improved sight for a projectile launcher which automatically compensates for the range of the target.
A yet further object of the instant invention is to provide an improved sight for a projectile launcher which is readily and quickly adjustable to account for the elevation of the shooter relative to the target.
A yet further object of the instant invention is to provide an improved sight for a projectile launcher which can be calibrated with targets at the same elevation at the shooter, and then used with accuracy when shooting from elevations which are relatively different from that of the target.
A yet further object of the instant invention is to provide an improved sight for a projectile launcher which is relatively rugged and which resists both bending and twisting deformations.
A yet further object of the instant invention is to provide an improved sight for a projectile launcher which is mountable on the lateral side surface of a bow riser.
A yet further object of the instant invention is to provide an improved sight for a projectile launcher which can be incorporated directly on the lateral side surface of the bow riser.
A yet further object of the instant invention is to provide an improved sight for a projectile launcher which can be protected from damage or disturbance by sight guard.
A yet further object of the instant invention is to provide an improved sight for a projectile launcher which may be used under conditions of low ambient lighting.
A yet further object of the instant invention is to provide an improved sight for a projectile launcher which may be readily adjusted while wearing gloves.
A yet further object of the instant invention is to provide an improved sight for a projectile launcher which is inexpensive to produce.
A yet further object of the instant invention is to provide an improved sight for a projectile launcher which is robust.
A yet further object of the instant invention is to provide an improved sight for a projectile launcher which can be used for either hunting or target shooting.
In accordance with these objectives, one feature of the instant invention is the incorporation of a conventional pendulum sight subassembly.
Another feature of the instant invention is the incorporation of a means for translating the pivot point of the pendulum sight subassembly to account for the elevation of the projectile launcher relative to the target.
Yet another feature of the instant invention is the incorporation of a calibrated means for translating the pivot point of the pendulum sight subassembly to account for the elevation of the projectile launcher relative to the target.
Yet another feature of the instant invention is the incorporation of an indexing mechanism in the means for translating the pivot point of the pendulum sight subassembly.
Yet another feature of the instant invention is the incorporation of a rotatable plate to which the pendulum sight subassembly is attached as the means for translating the pivot point of the pendulum sight subassembly.
The specific features of the instant invention provide a number of associated advantages. One advantage of the instant invention with respect to the prior art is that the pendulum sight subassembly provides for automatic compensation for target range.
Another advantage of the instant invention is that the means for translating the pivot point of the pendulum sight subassembly provides for compensation for the elevation of the shooter relative to the target.
Yet another advantage of the instant invention is that the indexing mechanism in the means for translating the pivot point of the pendulum sight subassembly enables ready and quick adjustment of the sight to compensate for the elevation of the shooter relative to the target, even under conditions of relatively low ambient lighting, or if the shooter is wearing gloves.
Yet another advantage of the instant invention is that the embodiment thereof can be compact, rugged, readily adapted to or incorporated on the lateral side surface of the bow riser, and amenable to protection by a sight guard.
Yet another advantage of the instant invention is that the embodiment thereof can be readily and inexpensively produced.
Yet another advantage of the instant invention is that by the incorporation of a pendulum sight subassembly to provide automatic range compensation together with the means to translate the pivot point of the pendulum sight subassembly to account for the elevation of the projectile launcher relative to the target, the instant invention is robust and can be used for either hunting or target shooting under a wide variety of operating conditions.
Accordingly, the instant invention provides for an improved sight for a projectile launcher which provides automatic compensation for target range, and manual compensation for the elevation of the shooter relative to the target in accordance with a predetermined calibration, whereby the sight may be calibrated at ground level and then used with accuracy over a range of shooter elevations relative to the target. The instant invention provides for an improved sight which is rugged and which is amenable to protection by a sight guard. The instant invention can be operated under conditions of low ambient lighting, or while wearing gloves. The instant invention is easy to produce, and can be embodied as either an attachment to an existing archery bow, or incorporated into the bow. The instant invention utilizes a conventional pendulum bow sightxe2x80x94which is commercially availablexe2x80x94as a subassembly.
These and other objects, features, and advantages of the instant invention will be more fully understood after reading the following detailed description of the preferred embodiment with reference to the accompanying drawings. While the description herein illustrates the application of the instant invention to the field of archery, one of one of ordinary skill in the art will appreciate that the instant invention can most generally be used as a sight assembly for any projectile launcher, particularly those such as bows, cross bows, sling shots, and air rifles for which the projectile velocity is relatively low whereby the associated projectile trajectory is significantly influenced by the forces of gravity or drag.